Method and apparatus for placing fluent material



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BY" @mw M. F. KEMPER Nov. 24, 1953 METHOD AND APPARATUS FOR PLACING FLUENT'MATERIAL M. F. KEMPER Nov. 24, 1953 vMETHOD AND APPARATUS FOR PLACING FLUENT MATERIAL 5 Sheets-Sheet 2 Filed May 21, 1947 5% a a R. l a m W A n a u M Inf w 3, N A .4i d 3 YJ E@ Nov. 24, 1953 M, F. KEMPl-:R

METHOD AND APPARATUS FOR PLACING FLUENT MATERIAL 5 Sheets-Sheet 5 Filed May 21, 1947 a. a/w/ arme/ver oww@ Nov. Z4, 1953 M. F. KEMPER 2,660,034

METHOD AND APPARATUS FOR PLACING FLUENT MATERIAL Filed May 2l, 1947 5 Sheecs-Sheet 4 NOV. 24, 1953 M. F, KEMPER 2,660,034

METHOD AND PPARATUS FOR PLACING FLUENT MATERIAL Filed May 21, 1947 5 Sheets-Sheet c o J5! giga @0.130

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VENTOR.

,arme/yer Patented Nov. 2"-1, 1953 UNITED siArss rarest OFFICE METHOD AND APPARATUS FOR PLACING FLUENT MATERIAL y Maxwell F. Kemper, Los Angeles, Calif.

Application May 21, 194.7, Serial No. 749,402

. 28 Claims. l

This invention relates to the lining of tunnels with concrete, and more particularly concerns an improved method and apparatus for the lining of small bore tunnels.

One method of lining tunnels is to load a number of cars with mixed concrete, form them into a train, and transport them into the tunnel where the lining operation is taking place'. With this method only the most inward car of the train is readily accessible for the emptying of its contents into the lining form. After this car has been emptied it must be moved out of the way so that the next succeeding car can be emptied.

In lining tunnels of large bore, the problem of shunting the empty cars to render the loaded cars accessible is not serious. However, when the tunnel is of such small bore that the cars can not pass one another, the problem of disposing of 'the emptied cars becomes serious. One solutionV would be to take in and remove one car at a time. This is obviously uneconomical, largely because of the prolonged idle time, during which the car is in transit; This Would be particularly objectionable in long tunnels.

AnotherY solution would be to provide a series of turn-outs along the length of the tunnel, by use of which the arrangement of the cars inthe train could be altered. This minimizes, but of course does not obviate, the shunting time required in transit between the working region and the nearest turn-out. Furthermore, it involves costly Vlateral excavation which ultimately must It is an object of thisvinvention to provide an 1;

improved method and' apparatus for the lining of 'small bore tunnels, which reduces to a large Y extent the idle time between unloading of the concrete laden cars of atrain.

, .it is lanother object of this invention to proi vide a method and apparatus for lining small bore `tunnels with concrete by the aid of which a train of concrete laden cars may be taken into a tunnel and the cars successivelyl emptied without requiring rearrangement of the cars in the train as the emptying proceeds. e l, l i

It is `a further object of this invention to proi vide amethod andv apparatus for lining small bore which obviates the necessity of excavating special 2 turn-out chambers in the tunnel, which must b refilled as the tunnel is lined.

It is another object to providein the art of lining smallbore tunnels, a method and apparatus by means of which a car for removing miscellaneous equipment, debris, and the like sometimes known as a muck car, may be positioned contiguous to the working region in the tunnel, at the same time that `cement laden cars are being emptied to form the tunnel lining. i

It is a further object of this invention to provide in the art of lining small bore tunnels, a method whereby a train of concrete laden cars may be taken into the tunnel,V the most inward of the cars emptied to Vform the tunnel lining then placed out of the way, and the succeeding cars 'may be emptied successively in a similar manner and placed out of the way. Following the emptying of all cars in the train, the vcars may then be hauled out of the tunnel.

It is a further object to simplify the lining of small bore tunnels by the provision of a single region from which substantially all the lining operations may be controlled at will, thereby minimizing the amount of time-consuming movement from point to point, sometimes required of tunnel lining operators.

This invention possesses many other advantages and has other objects which may be made more easily apparent from a consideration of one embodiment of the invention. For this purpose there is shown a form in the ,drawings accompanying and forming part of the present speciiication. This form will now be described indetail, illustrating the general principles of the invention; but it is tobe understood that this de'- tailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims. f

\ The principles of the invention will new be explainedy in connection with that type of concrete liningprocess in which compressed fair is cars into the tunnel over the track by means of i a small locomotive, generally electrically powered. In accordance, with-this invention, thereis provided a long sled which is adapted tobe pushed into the tunnel on the tracks. The-sled lt is customary insuch As illustrated in Figure 2, the car 29 has been emptied and moved onto the sled 25 being stopped at the inner end thereof by abutting against an upwardly extending angular member 33, detach ably secured on the inner end of sled 25.' Car 3| has likewise been emptied of concrete, and is in process or" 4being rolled up ramp 32 to rest on sled 25, where it will remain with the car 29 until the `train is re-formed andwithdrawn from the tunnel. With car 3l out of the way, the ramp 32 is then retracted within the sled 25, and the next car 31% is brought up against the outer end of sled 25 to have its discharge opening 23 con- -nested with the intake end 21 of conduit 24.

ing compressed air, and suitable connections for injecting the air into the cars.

As a rule, the compressors which supply air to discharge concrete from the cars into the conduit 2li are located at 'the mouth of the tunnel. The

compressed air is conveyed to Ithe operating region of the tunnel by means of a pipe 31, the inner end portion of which is made in the form of a flexible hose 33 to allow movementof the sled 25 and other equipment. The hose 38 is coupled to a pipe T 33 mounted on the member 33 of the sled 2d.

Compressed air passes from the pipe 31 through the hose 38 and T 3e :ln-toa vertically disposed pipe 4I, through T Rill, and 4thence into pipe 42 secured to the framework of the sled 2d between the side members thereof and extending generally parallel to conduit 24. The outer end of pipe 42 is adapted to communi'czfite upon appropriate connection, with air conduits provided on each of the cars'29, 3l, 3ft, where it serves to discharge 'concrete from the car to which it is connected into the material discharge line 2li.

To compensate for the pressure 'drop in the pipe 3i, there is shown, as provided in the inner end of the tunnel immediately adjacentform 23, a wheeled storage tank i3 connected to the air line 3B and ll-d2, at the T le by means of a flexible hose de. This tank i3 serves to stabilize the operating air pressure applied to the concrete carrying cars, and may serve additionally to provide a support for conduit 2d, adjacent the end of the form For this latter purpose an upright standard et is mounted atop tank e3, having a saddle at its upper end for receiving the conduit 241. Means such as a jack (not shown) may be interposed between the saddle and 'the lower portion of standardii for adiustably positioning the f end vof pipet with respect to the roof of the lining form 23.

f In practice, the form 23, although in several sections, isI generally of considerable length, so

that as concrete is discharged from-conduit 2t to allow full withdrawal of conduit 24 from above the form 23. The outer endl of cable 48 is anchored firmly, as by being secured to a post 48-a (Figure 2) embedded in the iioor of the tunnel excavation.

Compressed air for operating the winch 41 is supplied through a pipe 43 connected, within sled 25, to the main air supply pipe e2, as will be ex-jplained hereinafter. When air is supplied to the winch 41, the winding drum is driven in a direction to reel in the cable e8, thus causing the entire assembly, including conduit 2d, tank 3 and sled 25,5to move outwardly of the tunnel, away from form 23, thereby withdrawing the discharge end of conduitJ 24 to a position nearer the outer end of the lining space above form 23. `Althougl'i this operation is generally performed when there is no concrete-carrying train present, it is customary to provide suicient power in the4 winch d1 so that if necessary, such a train, including locomotive 35 and the concrete carrying cars 23, 3|, 34 etc., may be moved outwardly along track 22 if required.

Lining of the tunnel in the manner just disclosed is accomplished without disturbing in any way the track 22 or the pipe 31. Following such operation, the storage tank i3 and the winch car 4S are taken from the tunnel and replaced by a door lining apparatus commonly known as a stacker and denoted by the numeral 5l in Figure 3. As yshown in Figure 5, stacker 5I spans the licor of the tunnel, the edges thereof slidingon parallel trackways 54 formed at the bottom of the previously constructed concrete arch or lining 55. Stacker 5l has on its bottom edge, facing'into the tunnel, a screed 5&3 which serves to iced concreta onto the oor of the tunnel and to appropriately shape the upper surface of the concrete, thereby forming what is known as the tunnel invert 51. In Figure 5, the space to be occupied bythe invert is indicated by 51-a.

Stacker r5I is fed concrete from the concrete carrying cars 29, 3| etc., in a manner similar to that explained hereinbefore in connection with lining of the arch. In lining the invert however, the overhead portion of concrete carrying conduit 2t including the hoseZi is disconnectedv at the inner end of the sled 25 and removed, being replaced by a rigid, horizontal conduit 5d, the discharge end 59 of which feeds directly into the stacker 5i. The impact of the air-driven concrete mass is absorbed by aV baille tl mounted in front of the discharge end 5d o' the conduit 58. As the` forming of the invert 51 proceeds, the stacker tl is steadily withdrawn from the tunnel along the trackways Eil by means of an air operated winch t2 mounted on the stacker and fed by an air line 63. The winch t2 functions in sub- `stantially the same manner as winch di', and

includes a cable tima suitably anchored at a point remote from the stacker and wound on the winch and lls the lining space, it becomes necessary to `gradually withdraw the conduit. For this lpur-- Y wellknown in the'mining art. A cable i8 extends outwardly of the tunnel from the drum 151,` `bef tween the rails of track 22 for a distance suliicie'nt of the pipe 31 immediately in advance of the moving stacker. In addition, debris and mud,

'l known generally as muck, must be excavated from'the Vfloor of the tunnel in order to provide ya proper foundation Yfor' invert 51. n y To this end there is provided a muck car B4 which is placed on the inward end of sled 25, as shown in Figure 3, and which is therefore in the most convenient position to receive the track, pipe, and muck as they are removed from the floor of the tunnel in advance of the stacker l. It Will be readily seen by reference to Figure 3 that the provision of sled makes possible the positioning of the muck car E4 directly adjacent the working area where the muck and vmaterials no longer required must be removed from the tunnel door. At the same time, a concrete carrying car, such for example as the car marked 3 l, may be discharging concrete through the portion of conduit Zfi remaining on the sled and into the `conduit 53 and stacker 5I. A previously emptied car 2e is shown as also carried by the sled 25.

Conduit 58 is preferably made of steel and is of suiii-eient strength so that the Withdrawal of stacker 5l by the winch S2 pushes the sled 25, car 2l, etc., along the track 22 in advance of the stacker.

It will be seen that the method above described has the advantage of leaving the lined tunnel clean and free of debris, inasmuch as the arch is formed before the invert, thereby obviating the dropping of debris and grout from the arch were the steps to be reversed. This method has the further advantage of requiring only a single laying and dismantling of track 22 and pipe 3?, there being no necessity for elevating the track above the floor of the tunnel and forming thereunder the invert, as is the case with certain methods of tunnel lining.

Details of the method and apparatus hereinbefore generally described will now be described with reference to the remaining figures in the drawings. The sled 25 will irst be described, with particular reference to Figures 9, 10, 11 and le. 'Figures 9 and l0 show the outermost endportion of the sledwith the ramp 32 retracted. The sled 25 comprises a pair of parallel channel members t6, the top surfaces of which form the super-track onto which the cars 2S, 3|, etc., are rolled after discharging their load of concrete. Channel members 65 are connected at spaced intervals by cross members 61, thus forming the general framework of the sled. Arouate seats 63 are provided in the upper edges of each of the cross members (il for seating of the outer end portion oi the concrete carrying conduit 29, which is secured as by welding to the several seats. In a similar manner, the main compressed air pipe 42 is supported on the top of the cross members 6l, as is the winch air pipe 49. Pipe 49 is joined to supply pipe i2 at the juncture point 63, and

is provided with a manually operable valve 1l, by means of which the operation of the winch 4'! and the withdrawal of the conduit 24 from the form 23 may be controlled through operation of the reel 47.

A part of the length of each channel member d'5 is closed by plate i2, thereby forming guides for receiving the reciprocable rails 'i3 of the ramp 32. As shown in Figure 9, the outer ends of the rails i3 are beveled to provide a smooth, inclined junction with the respective rails of the track 2E, and are slidable on the rails 22, being maintained in proper lateral position by the connecting T-shaped cross member 14, the vertical leg or which depends below the top surface of the track and engages the inside edges of the track rails. The rails I3 may be slightly convex to provide a smooth transfer for the wheels of the cars from the ramp to the channel members 6.6.

To the inner ends of the two ramp rails I3 are pivoted actuating rods 15 which extend along the inside of channel members 66 and are connected at their inner ends by a yoke 16. Yoke 16 spans the several pipes 24, 42 and 49, and slides along the top of the conduit 24 as the ramp 32 is reciprccated.

Adjacent pipe 24 are mounted compressed air motive means, including an air cylinder 11 with a packed piston thereinl which serve to reciprocate the ramp 22. Piston rod 18 is connected to the piston in the cylinder 11 and is connected at its outer end to the yoke 'I6 by means of a pin 'I9 (Figure 14). The piston and piston rod T8 may be operated to move the ramp 32 in either direction by admitting air under pressure from the pipe 42 to the appropriate end of the cylinder 7l, and at the same time opening the opposite end of the cylinder 11 to exhaust. For this purpose the opposite ends of the cylinder TI are connected by a pipe 83, having a conventional manually operated lr-way valve 84 interposed therein. The inlet of valve 84 is connected by means of a pipe 85 to the main air supply pipe 42 at 85, the outlet opening to the atmosphere.

An air gauge Si may be installed in pipe 85 to conveniently indicate at all times the air pressure in the main air supply pipe 42.

In order to insure a smooth joint between the rear ends of the rails 'F3 and the corresponding outer ends of the channel members 66 forming the supertrack of the sled 25, means are provided for slightly elevating the inner ends of the sled rails 13 as the ramp 32 reaches its extreme extended position. This means assumes the form of a pair of foot members 88, pivoted respectively on the inner ends of the rails 13. The foot members 88 extend outwardly from Vtheir pivotal mounting, with their ends sliding on inclined plates 89 secured as by welding, below the channel members 56. At the outer ends of the plates 39 are welded stop members 9i against which the foot members 88 abut as the ramp 32 approaches its fully extended position. Further outward movement of the rails 'i3 causes the foot members 88 to swing upwardly about the stops 9 i, lifting the inner ends of the rails 13 and wedging them against the underside of the upper flange of the channel members 66, as shown in Figure 11. In this manner, a rm and smooth joint is formed at 92 between the extended ramp rails 'i3 and the sled rails 66, facilitating movement Vof the cars from the ramp 32 to the sled 25.

It will be noted that the foot members B8 are provided with toe plates 93, which are the actual engaging members abutting stop Si. As the foot members 88 swing upwardly, the weight of the rear end of the ramp 32 is shifted from the toe plates 93 and is assumed directly by the foot members 88 resting on top of the stop members 9|. Thus, the only function which the toe plates 93 fulfill is that of sliding on the plates t9 and of effecting the swinging of foot members SS by abutting the stop members 9|.

At its inner end, the sled 25 is provided with a pair of wheels S4. At the outer end, however, the sled 25 merely slides along the track 22 on a transverse cross member 95 secured to the bottom of the sled between the channel members 66. To prevent lateral displacement of the sled the member 95 is provided with a pendant flange 56 extending between the inner edges of the rails Vof the track .22.

aeedoee In order to connect the cement-carrying car which is to be discharged, to the conduit 24, as well as to connect the main air pipe 42 to such car, means are provided on the end of the sled 25 for simultaneously coupling the respective cement and air conduits of the sled to those of the car. Such means will now be described with particular reference to Figures 6, '1 and 8, showing one of the cement carrying cars, as for example car 29, coupled to the sled 25.

As explained hereinbefore, the intake end 21 of conduit 24 is rpositioned adjacent the outer end of the sled 25. In this position the intake 21 is adapted to mate with the end 23 or" the discharge conduit 91 of the car 29. The mating connection between conduits comprises a ring 9S welded around the outside of the intake 21 to form a female coupling for receiving the male coupling represented by the end 28 of the conduit e1. A. resilient gasket 99 is secured to conduit Q1, against which ring e8 is adapted to abut to provide a uid tight fit.

Each of the cars, as 29, is provided with an air pipe lill which is adapted to receive air from the main air line i2 when the car is connected in discharge relation with the sled 25. This couplingr will now be described. i

Functionally the only problem presented in effecting the air coupling is the simple one of providing an air tight joint between the pipe 42 and the pipe lill on the car 29. However, in view of the central positioning of the juncture` between the concrete conduits 24 and 91, a single coupling between air pipes 42 and |il| would, of necessity, render the overall connection unsymmetrical, and subject to leakage brought about by strains due to unbalanced pressures. The advantage of structural strength achieved through symmetry is particularly noticeable when it is necessary to move the coupled sled and car together over the track 22, as when the winch 41 is operated during the placing of the concrete.

To effect symmetrical coupling between the air lines 42 and ill, the sled 25 and each of the cars, for example car 29, are provided at their ends which are to be coupled, with transverse air chambers |62 and |23 respectively, which surround the ends of their respective concrete con-l duits 24 and 81. The pipe 42 extends completely through the sled air chamber |22 at one side thereof and terminates in a male coupling member |04. That portion of pipe d2 within chamber |02 is provided with a plurality of perforations |05 by means of which air from pipe 42 may enter freely the chamber |62. On the opposite side of chamber |62 there is a pipe me of the same size as pipe 42, which likewise extends through chamber |92, with its outwardly projecting end terminating in a male coupling member |61. Passage of air from chamber H22 into stub pipe |06 is effectuated by the provision or a plurality of perforations |02 in that portion of the pipe |115 which lies within the chamber |92. The rear end of the pipe Hl@ is closed by a cap H19.

The forward ends 'of the two air pipes 42 and i435, constituting the male coupling members loft and |91, respectively, are adapted to fit into openings in the vertical outerwall of the air chamber H33. The air pipelili communicates with chamber |23 as shown in Figures 7 and 13. It will thus be seen that through the use of the air chambers |62 and |23, and the provision of the stub air pipe 56, a iully symmetrical coupling between the sled 25 and the car2e is provided. To prevent escape of air about the pipes 42 and |02 when the chambers are in coupled relation, resilient sealing rings M14-a and HB1-a are pro- 'vided respectively about the pipes 42 and |05 so as to be compressed between the adjacent walls or" the chambers |l2 and |83 when in coupled relation (see Figures 8 and 10). The holes in the chamber walls for accommodating the pipes may be countersunk, as indicated for example at 42nd and lot-a in Figure 13, to improve the sealing leiect of these rings, if desired. If desired, the male coupling members |04 and |01 .of the air pipes 42 and |65, respectively, may be provided with lateral apertures to aid the flow of air vvfrom the pipes into the chamber |23. The air coupling assembly, including chambers |02 and |23, and the c-oupling members |24 and |01 is so positioned with respect to the central, concretecarrying conduits 24 and 91 and the respective juncture members 21 and 28, that concrete coupling and air coupling are eiected simultaneously as the car 29 is brought against the end of the sled 25.

To secure the car 2s and the sled 25 together 'during the discharge of concrete, the sled is pro- 'vided with a pair of hooks H2 'engageable with horizontal pins o-r bosses lextending outwardly from the opposite sides of the air chamber |23. Hooks H2 are braced by the transverse cross member H4 and are pivotally mounted at their ends on lever arms H5, which are in turn pivotally mounted at ||6 on a reenforcing band i iti-a encircling conduit 24, and air pipes d2 and m5, and appropriately secured thereto. As the lever arms i5 are raised by means of a transverse' handle H1, the hooks ||2 are moved outwardly to hook over the studs H3; upon lowering of the lever arms l E5, the hooks |2 are drawn inwardly, thereby drawing the car 29 firmly against sled 25 and sealing the air and cement connections described above. As seen in Figure '7, lever arms H5 are retained in position by being pivoted slightly past the center point to eiect over-center 'locking in the well known manner.

Application of compressed air from pipe i2 to the air conduit |0| of the car 2Q is controlled by a manually operable Valve lie inserted in the pipe i2 near the outer end of sled 25. Actuation of the valve I8 which is of a type commercially available, is achieved by rotation of its operatingV handle H9 about an axis parallel to the length of sled 25. Handle H9 is hinged at |2| in order that it may be swung downwardly into a horizontal plane to permit passage of the cars 29, 3|, etc., as they are moved onto or on the sled 25.

. The construction and operation of a typical concrete carrying car, such as the one indicated by 22, will now be described, with particular reference to Figures 6, 7 and 8.

The body of the car 29 for carrying the conu crete is in the form of a sealed container 29-a adapted to withstand the pressure of the air which serves to force the concrete from the container into the conduit 24. This container 29-a is shown as mounted on a rectangular frame 29-19, which may be conveniently formed of structural steel and is arranged to be supported on the track 22 by pairs` of axially aligned wheels 294 and .2S-d rotatably mounted on opposite sides of theframe ZS-b adjacent the opposite ends thereo-f. The general configuration and use of'this type of pressure vessel is illustrated and described 'in my prior Patent 2,313,826, and reference thereto is made for further details.

A conical hopper portion |22 of the container ZQ-a opens downwardly into the concrete discharge conduit 91. The rearof the conduit 91 terminates in an air control Valve |23 disposed at the edge of theA opening |24 in the lower' end of the conical hopper |22. The construction and operation of valve |23 is similar to that disclosed in my prior Patent 2,344,703, and reference thereto is made for a full understanding of its function and mode of operation. It will suce here to refer to Figure 8, which shows the air pipe |01 connected, as by a T |25', with the valve inlet |25. Valve inlet |26 communicates with the intake chamber |21 of the valve |23 (Figure '6), from which point, by opening of the valve |23, air under pressure may be fed into the end of the conduit 91, into which concrete passes by gravity from the hopper |22 of the container ZS-a.

Valve |23 is operated by means of a horizontal lever |28 pivoted at |29 and connected to a longitudinally reciprocable rodA 13| which in turn is pivotally connected to a hand lever |32, Which thus serves to open and close valve |23 as desired. Valve |23 is normally maintained closed by a. helical spring |33 surrounding the Vvalve stem, as shown in Figure 6. Upon manual actuation of lever |32 to open valve |23,l air flows from the main air pipe 42, through the coupling means including the air chambers |92 and |53, into pipe and through valve |23.' It forces concrete, dropping downward in the hopper |22,

outwardly of the conduit 91 and into the material discharge line or conduit 24. This general mode of operation is similar to that disclosed in my aforementioned Patent 2,313,826.

During transit of the cars, such as 29, 3|, 34 into the tunnel 2|, the conduit 91 is closed by a flapper valve |34, which may be opened and closed by means of a hand lever |35 connected to the valve member |34 by al linkage |36. Lever |35 may beA secured in its upward position, to maintain valve |34 closed, by means of a link |31 pivoted to thev outer wall of the container 29-a, which may be slipped over the end of the lever |35.

When the transit time between the loading of the mixed concrete into the cars and the emptying thereof Within the tunnel 2| is of extended duration, the concrete may acquire an objectionable set in the conduit 91 and in the bottom part ofy the hopper |22. I o prevent this setting of the, concrete, as welLas to prevent separation of the, solid constituents, means are provided for agitating the contents of the container 29-:1` through the u se ofv compressed air. For thisv purpose, the discharge opening 28 is closed, and valve |23 is slightly opened. to allow compressed air to flow into the rear of the conduit 91, thence upwardly into the container 29-a and through the concrete.

To achieve such agitation of the concrete, two especial features are provided on the container 29-a.. First, the cover |38, provided for the loading aperture, is designed so that it'may bev opened" slightly to allow escape of thev agitating air; yetV still prevent expulsion of the concrete asv thev airI is forced upwardly therethrough. The design of the; cover, or closure means, |38 will be described more particularly hereinafter. Itforrns the subiect matter of my U. S. Letters Patent; No. 2,565,029, issued August 2l, 1951.

The second feature is a cap |39, for supplementing the valve |34 and sealing the discharge opening 28 of the conduit 91.. This c ap |39 i s illustrated generally in Figure 6.and` shownV moreU particularly in Figures 12 and,` 13.v Cap |39 serves to insure tight closing of conduit91, sup.- plementing the valve |34I which is generally' not constructed to seal' against leakage of grout; and also permits niection oi` a counter-flow of agi'- tatmg air' through the provision therein of an opening' throughvwhich air under pressure may be admitted Yto theY discharge end 28Y of the conduit 91 simultaneously with the admission of air through valve |23. During the agitatingprocess, valve |34 maintained open, being hinged at |4| to swing into a recess |42 (Fig. 6) formed in the upper wall of the conduit 91. When air is thusforced intoY the hopper |22 -rom both the normal inlet |24 and the` normal' outletV 25, thorough agitation of thev concrete is effected, thereby completely obviating the chance formation of a plug Vof concrete, inthe conduit 951- which might prevent normal discharge of concrete from the conduit. i

Referringparticularly to- Figures 12 and 13', the cap |39 is shown hinged', by means of a bifurcated member |43, to the conventional coupling member |44 provided on the car., The arms |45 of the Vmember |43 are hinged to the car coupler |44 by means of bolts |46. The c ap |35 is normally swung back, out of the way, as shown in Figure 6; when occasion arises it may be swung downwardly to cover the discharge opening 25- of the conduit 91, asshown Figures 12 andl 163'.

TheV cap |39 is adapted to be secured closed position by means of a hook |41- pivcte-dat his to a pair of short' links |49 secured to a shaft |52' rotatably supported by the; car coupler |441 Anoperating handle |-`5| is fixedto the shaftV |52. By reference to Figures 6 and 12, it will be readily seen that clockwise movement of the handle |5| and shaft |52 will serve to cause hook |i1= to engage the lip of a cross member |53 secured between the arms |45; thereafter reverse movement of the handle |51 causes hook- |41 to draw cap |39 securely into position against the ring gasket 99l mounted' around the edge of thedischarge end 28 of the conduit 91. Cap |39 is maintained closed by over-centering the short link |39, as shownv in Figure 12.

In order to provide for the introduction of air into the discharge endv` 28 of the conduit 91, the

cap |'39i isprovided with an aperture into which is tteda pipe jointy |55, connected by a flexible hose |1551v to-a nipple |51 opening into the-air pipe |0 (Figure 7);.

I-t'vfil'll be understood? thatl introduction of agitatingair is; not required when they car 29' is coupled; to the` sled 215.10m-, instead; to beV eiiective, must be accomplished prior to the time that the car is ready for emptying into the con-duit 24. Thus, air for agitation is not introduced throughl the npr-mal-` air inlet chamber |03, but is introduced; through a special fitting |53' at the rear or the car 29; which j oins the T-junction |25 in. the air pipe |9|. During agitation, the air pipe must be isolatedifronr the intake chamber |93", otherwise the air wouldi simplyv escape throughl the; openings in the chamber. To pre-- vent such venting, a manually' actuatable valve Isl is provided iny the pipe m1 between the chamber |53" andthe T |51. Another air 'valve |62, locatedlat the endofthe hose |53, is normally maintained-` closed, being opened' only for the, special' step of introducing agitating air into the car 2 9? through the discharge opening 28.

In operation, an air line is attached to the fitting L58, and cap |g39 is, swung down and secured over the openingi 28 by means of hook |41; Air theniiows through two paths, the rst b eingjromiitting |j58;,t`hrough the valve |23, into the hopper |22 and upwardly through the conlili crete mixture. The second path foi` the air isV from fitting g, through pipe ||l|, to joint |51, through hose |56, and into the discharge opening 28 of conduit 91 through cap |39. Air is ius injected into the bottom of hopper |22 from both ends of conduit 91, thereby completely obviating the formation of plugs of concrete which might otherwise block the normal discharge of concrete at the desired time.

The foregoing described agitating feature, in which air is injected into the hopper |22 simultaneously from each side thereof forms the subject matter of my U. S. Letters Patent No. 2,534,270, issued December 19, 1950.

On very long hauls it maybe advisable to effect concrete agitation during the actual transit of the concrete carrying train.` For `this purpose, the auxiliary air tank 3E shown in Figure 1 may form a part of the train, thus providing during transit a source of compressed air which may be connected to the litting |53 at the rear of each ofthe cars as 29,31 and 34.

lt may also be advisable in certain cases to introduce additional water into the concrete mixture before its discharge into the conduit 24; and to this end the water pipe |63 which is customarily laid during the excavation of the tunnel 2| is allowed to remain during the lining operation, to provide a source of water in the working region of the tunnel.

The specially designed closure means |38, which facilitates the agitiating operation hereinbefore described, will now be described with reference to Figures 6 and 15. As shown in Figure 6, the container 29-a of car 29 is provided with a loading aperture |555 through which concrete may be poured into the car. A frame |55 serves to define the aperture It andextends into the container 2ta a short distance for supporting a sealing gasket |12. Beneath the opening lts, there is provided a closure plate It mounted on the end of an arm |51, which is shown as formed integrally with a vertical, rotatable shaft |68 suitably jo'urnalled in the top of the container S-a. A horizontally extending handle |69, mounted on the upper end of the shaft |68, provides a means for rotating the shaft and thus swinging the arm |t1 and the plate |56 away from the opening |64, to the position shown in dotted lines in Figure 15. Seating of the closure plate E656 against the under rim of the frame |55 is effected by mounting the shaft |68 in its supporting bushing |1| so as to permit axial movement thereof. Thus, after plate |65 has been swung into position directly under the opening it, upward sliding of shaft |68 serves to force 4 it against the gasket |12, thus sealing the opening.

Raising o1" shaft |58 is conveniently eiected by pivotally connecting arm |59 to shaft |63, as shown at |13, and providing a fulcrum about which the pivot point |13 may be raised by `verticai movement of the outer end of the arm its.

VThe fulerum is formed by a horizontal groove |14 14 |69 may be maintained in position by a smallbrace member E11 hinged to the top of container 2li-a and engageable in one of the notches |18 formed on the underside of the arm E69.

To insure proper seating of the closure plate |56 against the gasket |12, the arm itil is attached to the plate |56 by means of a loosely tted pin |19, thereby allowing limited universal movement of the plate |55 with respect to the arm. The swinging of plate |65 is confined to about a angle, as shown in Figure 15, by the provision of pendant stops |8| on the underside of the top wall of the container ZS-a.

By dropping the brace |11, thereby allowing shaft |68 to drop to its lower position, the closure plate |65 may be moved slightly downwardly from the gasket i12. rhis provides an annular space permitting escape of agitating air, while still retaining closure plate li over the face of the opening |512 to prevent any substantial expulsion of concrete.

Each of the cars in the train, including the auxiliary tank car 3d, is provided with a coupler IM similar to the coupler shown in Figures 12 and 13. The coupler its has an outwardly facing slot |82, the top and bottom walls being apertured at |33 for the reception of a suitable coupling pin (not shown) which engages a coupling bar or link itil-a joining adjacent cars (Figures 1 and 2). A. generally similar coupling arrangement is provided between the sled 25 and the winch car d5, and between the winch car d6 and the storage tank car t3.

The method of using the apparatus will now be explained.

Following excavation of the tunnel 2l, during which the track 22 is customarily laid, a given length of lining form 23 is erected. For this purpose, timbers 19| are placed along each side oi the track 22. Bracing between the timbers al is provided at intervals by transverse timbers le?? resting atop the track .22 and extending between the inner sides of the timbers iti. rThe bottom edges |93 of the form 23 are then secured along the top edges of the timbers 19|, adjustable positioning thereof being achieved by the use of wedge members |95 in any suitable, known manner.

The concrete conveying conduit 2li is then advanced into the arch-shaped lining space, being slid along the top of form. 23 until the discharge end thereof is positioned adjacent the inner end of the form. The concrete feeding assembly, consisting of the storage tank i3 coupled to the winch car 45, in turn coupled to the sled Eil, is then disposed on the track 22 just outside the `form 23, as shown in Figure 1.

A train of concrete laden cars, such for exaniple as cars 29, 3|, 34, is then pushed into the tunnel by suitable means, such as the locomotive 35. If the tunnel length is great it may be desired to include in the train the auxiliary tank car 36 containing compressed air. In this way, a'source of air is provided for agitating the concrete mixture during transit, in the manner previouslydescribed in my aforementioned Patent No. 2,534,270.

The train having reached the working region of the tunnel, the most inward car 2S is pushed against the sled 25, either by hand or by the locomotive 35. This connects the discharge end ES of the car conduit S1 and the intake end 21 of the material discharge line 2t. Simultaneously, the two nozzle members llli and |61 forming the outlets of the air line 112 engage the symmetrically disposedlopenings in the air chamber itt on the car' 29. By' referring to Figure 'l it will be seenl that the hooi;- members H2 are so formed and are so connected to the arms H5,- that with the arms in their lowered normal positions, the outer ends of the hooks H2' will be engaged by the bosses H3, formedin 'th-e chamber w3, being raised thereby as the car is moved into connected position, to allow the bosses to'V pass under them. Thereafter, the arms H5 are raised by meansv of a handle i il, causing the hooks H2 to drop over the .bosses H3. Returning the arms H5 to their horizontal position draws the car 23 firmly against the sled 25, sealing the air and concrete couplings. Iit will be obvious that the car 25 preferably should lceuncouple'd from the train before operating the handle lll to draw the.y car into sealing position. This' couplingv position is. maintained by the over-center acti-on' of hook members H2 about the pivot points iiS-a ofthe arms H5.

The hinged handle l i9 of the valveh H8: on-th'e' sled 25 is then raised (Figure 7)', and the valve is opened by appropriate movement of the l'ran'dle'.` This operation supplies air under pressure from the pipe 42, through the air` chambers MIZ and lilB, to the pipe iili, and` thence to the valve chamber 21 (Figure 6). Handle ISS1 on the car 23 is then iowered, raising' flappe'r valve i3d into` the recess H252v by means of the linkages E35'. The car is then ready to deliver its load of.' concrete into the conduit 24.L This is' effected at' any desired time by appropriate operation of the valve i23.

Following emptying of the. car 29, the armsi5 are raised to release the hooks l i2 from the' bosses I i3. As the arms l i5 are lowered, the hooks' H2 are lifted slightly' by means of' the cross piece' tid to prevent reengagement of hooks i l2 with' the' bosses l i3.

Car 29 is then ready to be shunted out of the' way onto the sled 25. This is effected by rst backing the emptied car 25 away from the' sled 25 a sufficient distance' to allow extension of ramp 32. This accomplished, the four-way valve' 8'4 (Figure 10) is actuated' to apply air pressure to the right hand' end of the'cylin'der- '17,A thus drawing the piston rod 78 into' the cylinder, and' by means of the actuating rods t5, coupled to. piston rod E8 by yoke it, forcing the ramp 32 outwardly of the sled 25. Upon engagement of the toe plates S3 with stop !ll,.thev inner endsof rails- 63 pivot upwardly about the stop members' 9| and are wedged against the underside of the channel members 66, as shown` in Figure: lfl.

Car is pushed up the ramp' 32 a-n'd thence` to the inner end of thev sledl 25:, where it is stopped by abutment of its wheels with the in'clined end member 33` of the sled 25". Ramp 32'Y is' then" retracted by actuating'valv'e 84 to apply'a'ir' pressure to the' left hand or outer end' of the cylinder il, thereby forcing the piston rod 18? out of the cylinder and moving the ramp 32. to the right from the position shown'. in-Figure' 11=. This'l drops the foot members 38 tov their' generally horizontal position', and then: retract'sf the ramp' 32 to the position, as shown in FigureA 9?.

Each of the succeeding cars 3|' and 34' is: then emptied in a similar manner', the former being also moved onto the sled 25, as shown' in Figure' 2, to make room for the nal car' 3'41 Following emptying of all the cars, the train is' reformed and taken out ofthe tunnel' 2l` to make roomfor another concrete laden train'.y Although the" apparatus has been shownand describedV as'Y utilizing4 three concrete carrying cars, it is` not tunnel oor or invert.

l5 necessarily so limited, and may be adapted readily for use withY a greater number of cars.

During use of compressed air, the normal flow of air is from air pipe 31 into flexible hose 3B, T 39, Vertical pipe 4l, pipe 42, and thence into th'e air pipe IOI of the car being unloaded, for example car 29, as explained above. A substantially uniform air pressure is maintained during intermittent use of the air by employ- :nent of the storage tank 43, which is connected to' the air line' by means of the hose 44 coupled to' the T 39'.

As th'e placing of the concrete progresses, and the inner portion of the space' above the form 23 fills with concrete, the discharge end of the conduit 24 becomes' embedded therein. Thus, it is' desirable that the conduit 24 be moved back out of the lining space as the work progresses, so' that the back pressure against which the concrete mustvbe discharged, is decreased. This isy effected by the air operated winch 41, which is operated to wind in the cable 43, by compressed air supplied through the valve "il, conveniently located near' the outer end of the sled 25. As the space between the support 45, mounted atop tank. 43, and the outer end of the form 23 increases due to the withdrawal of the conduit 2li, suitable supports (not shown) may be placed under the conduit 24 at appropriate points.

Following completion of the arch lining 55 (Figure 5)", the stacker 5f is` takeninto the tunnelv and. a section of suitable length behind the stacker' (see Figure 3)` is cleared of pipe, rails, etc., and appropriately excavated for the The sled 25 is returned to the working; region of the tunnel without the winch car 43 and the' storage tank 43. On the inner end of the` sled 25 is the muck car 64, which receives the dismantled' and excavated material from the region 65. As shown in Figure 3, the inclined forward portion 33 of the sled' 2:5: is' removed for' the floor forming operation, as' are also the upstanding air pipe il and T 39: Thefiexible air hose 38 is then connected to the air line' 42 through the T 282. A transverse cross' member (not shown) is substituted for' the' end member 33. The removal of the forward. end portion 33 of the sled serves to render the muck car 6'44 readily available from the regiony 65.

Ther several concrete laden cars' 23, 3l and 34 are connected successively to the sled 25, in the saine. manner. as when effecting the lining of the arch; Thev stacker 5| is steadily pulled outwardlyf' of the tunnel as the concrete-is discharged, by operationy of the winch 62, supplied with air through. the' air line 63 connected with the air line 49' of the' sled 25, and controlled by the valve TI. As the: stacker 5| is moved outwardly of the tunnel, it pushes ahead of it the rigid, concrete-carrying conduit 58, which in turn pushes the' sled. 25, and any car, such as car 3|, which m'ay be connected to the sled. During this operation, the screed 56 on the inner end of the stacker 5l smooths the invert 5l' and forms it into the desired floor shape illustrated in Figure 5.

If desired, a small wheeled platform (not shown), adaptedto ridev on the shoulders at the bottom of the' arch: 55, may be provided behind' the stacker 5I to carry one or more finishing op'erators who give av smooth final finish to the top of the' invert 5l.

Stackers of this general' type 'are well known the art, butl heretofore they have not operthe delivery of concrete from successive cars in a train and the provision of the muck car immediately adjacent the working area.

The final step may comprise treating the inner surface of the entire lining with a curing liquid to properly control the rate of drying.

From the above it will be apparent that there has been disclosed a method and apparatus whereby a series of individual, concrete-laden cars may be moved into a small bore tunnel, and the cars successively emptied, without the need of shunting the cars by means of turn-out, passing tracks,V or structure requiring superfluous excavation. It will be seen that the method of this invention is carried out in a single region in the tunnel in close proximity to the actual working area of the tunnel, thereby eliminating extensive moving about ci the operators. It will be further seen that ope'zation is eiectuated and controlled from a single position, namely, the region adjacent the outer end of the sled 25, where all the controls are located.

Thus, it is at this point that the car to be unloaded is connected to the conduit 24 and to Athe air line 412, and the main air valve H8, the ramp controlling valve 84, and the valve 'Il controlling the winch 41 or 62 as the case may be, are operable.

I claim:

1. The method of forming the top and side Walls of a'small bore tunnel having a form for defining the inner surfaces oi said walls, as well as a material discharge line extending longitudinally above the form for conveying the Wall material to the desired location in the form, which comprises: advancing a train of loaded mobile containers to the working region in the tunnel; connecting the most forward container to said discharge line; discharging the material from said container; disconnecting said container from the discharge line; advancing said container along said line; and connecting the suoceeding container of the train to said discharge line.

2. The method of forming the door of a small bore tunnel, which comprises: delivering the floor material through a material discharge line from a mobile container connected to said line; forming the floor surface while withdrawing said line and said container in accordance with the delivery or the material; disconnecting said container, when empty, from the discharge line; and advancing said empty container along said line tok provide for connecting a laden container to said line.

3. The method of forming the floor of a small bore tunnel, which comprises: clearing the bottom of the tunnel and excavating to an ap propriate depth, in a working region of the tunnel; delivering floor material through a material discharge line from a mobile container connected to said line, forming the floor surface as the delivery proceeds; providing a mobile vehicle between said container and said excavation for the excavated material and debris; and withdrawing said conduit, said container and said vehicle in accordance with the delivery of said material.

4. The method of forming the floor of a small bore tunnel, which comprises: clearing the bottom of the tunnel and excavating to an appropriate depth in a working region of the tunnel; delivery floor material through a material discharge line from a mobile container connected to said line; forming the floor surface as the material delivery proceeds; supporting a mobile vehicle above said line between said excavation and said container, for receiving the excavated material and debris; withdrawing said container, said conduit and said vehicle in accordance with the delivery of said material; and moving said container when empty, to be supported above said line to provide for connecting a filled container to said line.

5. In material handling equipment: a mobile container having a discharge opening adapted for connection to a conduit upon advance of said container to discharging position; and mobile means for supporting said conduit and said container, and a ramp operatively connected with said mobile means and over which said container is movable from said discharging position onto said mobile means to permit the contents of a succeeding container to be discharged through said conduit.

6. In material handling equipment: a plurality of mobile containers coupled to form a train; each of said containers having a discharge opening adapted respectively for connection to a conduit, upon advance of the container to discharging position; a vehicular support for said conduit, and means over which the containers are movable onto said support after the contents thereof had been discharged through said conduit.

7. In material handling equipment: a mobile container having means forming a discharge opening adapted for connection to a material discharge line, upon advance of the container to discharging position, said opening being directed in the direction of advance, a mobile support for the discharge line, disposed in advance of said container, and means between said container and said support over which said container is movable onto said support past the intake end of said line, whereby the opening in a succeeding container may be connected to the intake of said line while a container is mounted on said support.

8. In material handling equipment: a mobile container adapted for operation on a track comprising a pair of parallel spaced rails; a sled structure movable along said track; providing a pair of rail forming members for supporting said container above the track; a discharge conduit supported on said sled structure for movement therewith and adapted to be connected with the mobile container for discharging the contents of the latter at a point forwardly of said sled structure, an extensible ramp carried by the sled providing inclined rails extending upwardly from the track rails to the sled rail surfaces; and optionally operable means for projecting and retracting the ramp with respect to the sled.

9. In material handling equipment: a sled structure for use with a track having a pair of spaced parallel rails, comprising a pair of side members joined in spaced parallel relation and providing respectively rail surfaces above said rails; means including a pair of elements providing inclined surfaces adapted to extend upwardly from said rails to said rail surfaces on said members and slidable respectively in said side members; and means including a power cylinder for optionally moving said elements to telescope in the respective side members, or to extend therefrom.

10V. In material handling equipment, a sled structure for use on a track having a pair of is parallel spaced rails, comprising a pair of side members joined in spaced parallel relation, and a conduit extending between said members with its intake adjacent corresponding ends of said members and adaptedl for connection to a mobile container on said track, optionally operable extensible means on said structure providing inclined rail surfaces from said rails to the tops of said members for facilitating movement of said container from said track to said sled, said sled serving to support said container above said conduit for movement lengthwise thereof.

11. In coupling means for a pair of axially aligned main pressure conduits, as well as for a pair of supplemental pressure conduits; means forming a pressure chamber extending about each of said main conduits and maintained out of communication therewith, and respectively communicating freely with said supplemental conduits; means urging said pressure chambers together; means maintaining said supplemental conduits respectively in continuous communication with said chambers; means forming a pair of nozzles extending between said chambers when coupled and symmetrically disposed on opposite sides of said main conduits, for transferring fluid pressure between said chambers about said nozzles; and means for connecting said main conduits in fluid tight exchange relation when said chambers are coupled.

l2. In coupling means: a pair of axially aligned main conduits; means forming a pressure chamber extending about each conduit; means urging said pressure chambers together; a supplemental conduit on one side of said main conduit extending through and beyond one of said cham-- bers and providing a nozzle adapted to enter an opening in the adjacent wall of the other chamber when the chambers are coupled; and means forming a nozzle symmetrically disposed on the other side of said main conduit with respect to said supplemental conduit, extending from one chamber and adapted to enter an opening in the adjacent Wall of the other chamber; means including said nozzles ior admitting fluid pressure from said supplemental conduit into each chamber; and conduit forming means leading from the other chamber.

13. In combination: a mobile container for uent materials, adapted for advance along a guiding track, said container having a discharge conduit at its lower end directed in the direction of advance; Ya movable sled structure on said track, providing surfaces for guiding said container oifset from said track; a material discharge line having a portion xed to the sled, said conduit being normally aligned with said discharge line for connection therewith in iluid tight relation; and optionally operable means for causing movement of said container to said guide surfaces in response to advance of the container; the offset being such as to position said conduit for longitudinal movement along said line.

14. In combination: a mobile container for fluent materials, adapted for advance along a guiding track, said container having a discharge conduit at its lower end and a uid pressure conduit respectively with openings directed in the direction of advance; a movable sled structure on said track; providing surfaces for guiding said container offset from said track; a material discharge line and a fluid pressure line, each having a portion xed to the sled, said conduits being normally aligned with the respective discharge lines for connection therewith in fluid tight relation; and optionally operable means for causing movement of said container to said surfaces in response to advance of the container, the offset being such as to position said conduits for longitudinal movement along said lines.

15. In combination; a mobile container for fluent materials, adapted for advance along a guiding track, said container having a discharge conduit at its lower end opening in the direction of advance; a movable sled structure comprising a pair of side members disposed respectively above the rails of said track and forming an elevated track for said container; a material discharge line having a portion extending between said side members, adapted for connection with said con.- duit opening; and optionally operable means for causing advance of said container to raise said container to the elevated track, said elevated track being of such height as to position said conduit above said line to allow advance of the con.- tainer past the end of said line.

16. In a quick acting coupling for connecting a pair of members; a lever arm pivoted on one of said members for movement about a horizontal axis adjacent one end of the arm, a hook member pivoted on said arm at a point spaced from said axis for engaging a bossy on the other member, and extending over the pivoted end of the lever., move.- ment of said lever to coupling position causing said pivot to pass below a line joining said axis and said boss, means to limit movement of said lever in coupling direction, said member being adapted to rest on the end of said lever when not engaging said boss, said lever, when in. its limiting position, being freely swingabler upwardly to permit passage of said boss to coupled position.

17. In material handling equipment'. a sled structure for use with a track having a pairr of spaced parallel rails, comprising` means providing a pair of supporting surfaces vertically spaced above each rail; a pair of elongated elements, the inner ends of said elements being slidably supported respectively above the lower of said surfaces, the outer ends of said elements being slidably supported respectively on said rails; means for advancing said elements with respect to said surfaces; means for elevating said inner ends respectively to substantial alignment with the. upper of said surfaces,y said means comprising a pair of members respectively carried by each of said surface providing means and each of said elements and engageable upon a predetermined outward movement of said elements, one member of each pair being mounted for rotation upon engagement with the other member of the respective pair; and means for limiting rotation of said members when aligning position is reached.

Y18. In material handling equipment: a sled structure for use with a track having a pair of spaced parallel rails, comprising means providing a pair of supporting surfaces vertically spaced above each rail; a pair of elongated elements slidably supported respectively at one end on said rails, the opposite ends being supported respectively by forwardly inclined rotatable foot members engaging the lower surfaces; means for advancing said elements with respect to said surfaces; stop means for causing said foot members to rotate in response to advance of said elements, the rotation of said foot members causing said opposite ends to align substantially with said upper surfaces; and means for limiting rotation of said foot members when aligning position is reached,

19. In material handling equipment: a sled structure for use' with a track having a pair of spaced parallel rails, comprising a pair of side members joined in spaced parallel relation and providing respectively rail surfaces as well as supporting surfaces above said rails; means including a pair of elongated elements adapted to extend upwardly 'from said rails to said rail surfaces, the outer ends of said elements being slidably supported on said rails respectively beyond the ends of said supporting surfaces, the inner ends of said elements being slidably supported on said supporting surfaces respectively: means for moving said pair of elements with respect to said members; and means operative in response to arrival of the inner ends of said elements adjacent the outer ends of said supporting surfaces toraise the said inner ends, causing said elements to form a ramp between said rails and said rail surfaces.

20. In material handling equipment: a sled structure for use with a track having a pair of spaced parallel rails, comprising a pair of side members joined in spaced parallel relation and providing respectively rail surfaces as well as supporting surfaces above said rails; means including a pair of elongated elements adapted to extend upwardly from said rails to said rail surfaces, the outer ends of said elements being slidably supported on said rails respectively beyond the ends of said supporting surfaces; means for moving said pair of elements with respect to said members; a forwardly directed foot member pivotally mounted on the inner end of each of said elements slidably supporting said inner ends on said supporting surfaces; stop means adjacent the outer ends of said supporting surfaces for engaging said foot members and rotating them about their pivots in response to a predetermined outward movement of said elements, whereby the inner ends of said elements are substantially aligned with said rail surfaces; and means for limiting rotation of said foot members upon said elements reaching aligning position.

21. In material handling equipment: a sled structure movably mounted on a track; a materials discharge conduit mounted on said sled having an intake adapted for connection with means forming a discharge opening on a mobile material container on said track; means carried by said sled adapted to form a ramp for facilitating movement of said container from said track on to said sled; and means on said sled for supporting said container clear of said conduit to permit movement of said container along said sled.

22. In material handling equipment: a sled structure comprising a pair of side members, movably supported on a track having a pair of spaced parallel rails, said side members respectively providing rail surfaces spaced above the rails of said track; a materials discharge conduit mounted on said sled intermediate said members and extending longitudinally of the sled, said conduit having an intake opening adjacent the rear end of the sled, said intake being adapted for connection with means forming a discharge opening of a mobile container on said track; extensible ramp forming means carried by said sled structure adapted to facilitate movement cf said container from said track onto said sled structure; said rail surfaces being so spaced with respect to said conduit that, when said container is on said surfaces, said discharge forming means is clear of said conduit, to permit longitudinal movement of said container on said sled.

extensible 23'. In material handling equipment: `a sled structure movably mounted on a track; a materials discharge conduit and a fluid pressure conduit mounted on said sled and adapted for connection respectively withmeans forming a discharge opening and a fluid pressure inlet on a mobile material container on said track; extensible means carried by said sled adapted to form a ramp for facilitating movement of said oontainer from said track onto said sled; and means on said sled for supporting said container clear of said conduit to permit movement of said container along said sled.

2li. In material handling equipment: a sled structure movably mounted on a track; a materials discharge conduit and a fluid pressure conduit mounted on said sled and adapted for con-V nection respectively with means forming a discharge opening and a iluid pressure inlet on a mobile material container on said track; extensible means carried by said sled adapted to form a ramp for 'facilitating movement of said ccntainer from said track onto said sled; fluid pressure responsive means for operating said extensible means; optionally operable control means for admitting iiuid pressure from the iiuid pressure conduit to said uid pressure responsive means; and means on said sled for supporting said container clear of said conduits to permit movement of said container along said sled.

25. In material handling equipment: a sled structure movably mounted on a track comprising a pair of spaced parallel rails; a materials discharge conduit mounted on said sled and having an intake adjacent the rear of the sled; means for coupling a mobile container on said track, to said sled for movement therewith along the track; said container when coupled, having a discharge opening communicating with said intake; said sled structure including means forming a pair of rail surfaces spaced above said track for optionally mounting said mobile container for movement independently of said sled.

26. The method of forming a structure in a small bore tunnel wherein uent material for forming the structure is contained in a plurality of mobile containers disposed in line in the tunnel, and wherein the fluent material is subject to being discharged from said containers through a discharge conduit extending along the tunnel to a zone therein where the structure is to be formed; there being a longitudinal space in the tunnel between the ends of the conduit for accommodating at least one of said containers, which comprises: advancing the foremost container to a position adjacent the outer end of said space, connecting the foremost container with said conduit and conducting the material therefrom to said zone, disconnecting said foremost container from said conduit, advancing said foremost container into said longitudinal space, advancing the succeeding container to a position adjacent the outer end of said space, and connecting said succeeding container with said conduit for conducting the fluent material therefrom to said zone.

27. The method of forming a structure within a small bore tunnel in which are positioned a structure-defining form and a discharge conduit for conducting uent material to said form, which comprises: advancing in line in the tunnel, containers loaded with fluent material; moving the foremost container to a position spaced from said form, connecting said foremost container with said conduit for conducting the material to said form, disconnecting saidl foremost'` container from said conduit, movingf said foremost container from said position toward said form, `advancing thev succeeding container to said position, and connecting said succeeding container with said conduit for conducting additional fluent material to said form.

28. The method of forming a structure Within a small bore tunnel in which are disposed a structure-defining form and a discharge conduit for conducting uent material tosaid form, which comprises: advancing in line in the tunnel, containers loaded with fluent material; vmoving the foremost container to a position spaced from said form, ,connecting said foremost container While at said position with said conduit, forcing theV material from said foremost container through said conduit to said form, disconnecting said foremost container from said conduit, eiecting relative movement between said foremost container and' said conduit to dispose one above the other and said foremost container between the 24 intake endof: the conduit'andisaid form, andv advancing the container next in line and connecting it-.wthsaid conduit for conducting additional uent material .to said form.

MAXWELL F. KEMPER.

Referencesy CitegiLA in the le of this patenj.4

UNITED STATES PATENTS Number Name Date,-

5,18,394 Coyle Apr. 17, 1894. 1,290,459 Wi1son. Jan. 7, 1-919. 1,419,675 Huwyler June 13, 1922 1,553,476 Schuster Sept. 15, 1925 1,923,303. Fortier Aug. 23,A 1933. 1,981,883. Tappan Nov. 27, 1934 2,013,345 Gellatly Sept. 3, 1935- 2,190,727 McKenna Feb. 20, 19.40 2,313,826 Kemper Mar. 16, 1943 2,370,427 Sherry Feb. 27.-, 1945 2,419,329 Wilson v Apr. 22 1947- 21,429,045 Bellows Oct. 14, 1947 

